Research On Flexible Bionic Mechanical Structure And Control System Based On Ionic Polymer Metal Composite

Ionic Polymer Metal Composite(IPMC),as a typical flexible intelligent material,has shown great prospects in the field of flexible machinery,especially in the field of driving bionic machines.It is of great significance to realize independent operation and speed control of IPMC driven bionic machine for promoting its practical application.However,most of the existing IPMC driven bionic machines are controlled by open-loop mode without speed feedback control.Therefore,taking robot fish as an example,this paper mainly studies the structure and control method of the IPMC-based bionic machine,realizes the independent accurate speed control on the basis of a feedback control system,using,MPU6050 sensor inside the robot fish to measure its swimming speed.The traditional PID control system and the fuzzy PID control system were first established and simulated in Matlab respectively.The simulation results showed that the response time of the fuzzy PID control was 0.1 seconds,which was obviously less than 0.6 seconds of the traditional PID control.Compared with traditional PID control,the maximum overshoot of fuzzy PID control was reduced by 64.7%,and the steady-state error was reduced by 76.9%.On this basis,the schematic diagram of control circuit was designed,the prototype of the robot fish was made,and the swimming speed control experiment was carried out.The experimental results were consistent with the simulation law,and it showed that the fuzzy PID control could reach the preset speed and swim stably faster than the traditional PID control,and the steady-state error was reduced by 48%.Overall,the control effect of fuzzy PID control system was obviously better than the traditional PID control system.By imitating the form and movement mode of fish,this paper also designed the body structure of robot fish driven by pectoral fin and caudal fin,and based on this,a control system was designed that can output three independent square wave voltage signals.The control system mainly included micro controller unit,driving signal generation unit,speed measurement unit,automatic obstacle avoidance unit and voltage conversion unit,which can realize the straight line,turning,acceleration and deceleration of the robot fish swimming,and carrying the infrared sensor of obstacle avoidance and allowing the autonomous obstacle avoidance of robot fish when swimming with high flexibility.In addition,inspired by movement mode of looper and butterfly,a worm robot and a butterfly robot were also designed and carried out experimental verification,both of which can achieve good movement.In addition,a scheme of a stepper motor based on IPMC was also provided.This paper provides important research basis and abundant experimental data for the subsequent design and production of flexible robotic fish with more complex structure and stronger function,and also has certain guiding significance for the future development of IPMC-driven flexible bionic machinery.